Sprouts and microgreens are foods produced by exposing seeds to water, light, and other conditions that allow the seeds to germinate and grow into tiny plants. Seeds that germinate into edible small plant forms include, for example, alfalfa, clover, cress, kale, mung bean, radish, mustard, broccoli, onions, flax, green peas, sunflower, corn, wheat, oats, barley, rye, soybeans, and others.
Seeds used in the growth of sprouts are generally purchased and/or obtained from farms. There are no particular precautions to keep the seeds clean and microbe free thus the seeds may contain bacteria, viruses, fungi, or other organisms that can be harmful to public health. The presence of microbial pathogens such as E. coli Ol57:H7, Salmonella, Listeria may be harmful to the health of the consumer. In addition, seeds may be contaminated with other organisms that may interfere with the quality of sprouts by imparting to them a bad flavor or color or by reducing shelf life. The addition of water as well as the handling and manipulation of the seeds during the growth and packaging of the sprouts can also introduce undesirable microorganisms.
Sprouts and microgreens have been grown by methods that include rinsing the seeds, sanitizing the seeds, placing the seeds in trays or drums at ambient temperature to allow for growth to marketable size. When seeds are sprouted in rotating drums, the seeds are watered approximately every 30 minutes. When the sprouts are fully grown (˜4-5 days), the sprouts are rinsed, dried and packaged for sale in either bags or trays. The safety of the sprouts is generally reliant on the disinfection of the seed and the testing of waste irrigation water for the presence of pathogens. The disinfection is not reliable and furthermore the pathogenic organisms may be introduced and allowed to grow during the manufacturing process. Alternatively, seeds for sprouts or microgreens may be placed in retail containers, with irrigation holes in the bottom, over a foam or an absorbent material such as cellulose and sprouted in the same container in which they may ultimately be delivered to consumers. The containers are placed on trays and the growing sprouts are irrigated from overhead or from the bottom tray with the seeds being irrigated periodically via holes in the container. At the end of the growth cycle, the prior art containers are capped with a lid, labeled and sent to the market with open irrigation holes, which compromises the sanitary condition of the product and its package. Again, the pathogenic organisms may be introduced and allowed to multiply easily during the growth of the sprouts, especially during irrigation.
Methods are also known that use water-retaining media such as agar in a container that can be shipped. The seeds or germinated seeds are placed directly on the water-retaining media so that the seeds use the water from the moisture-retaining layer for growth. The containers are first shipped at temperatures appropriate for growth generally about 70° F. and after several days stored at a storage temperature of about 45° F. after completion of growth. This system optionally uses two phases of temperature, one for growth and one for storage. Pathogenic bacteria could still be present and multiply rapidly during the growth phase of the sprouts leading to high levels of undesirable pathogenic bacteria.